Static IP on workstation which connect to ip phone

[zheepern0826]

Hi guys,

I am connecting my workstation to my IP Phone and there is another port from IP Phone is connecting to the wall jack.

I will need to configure my workstation by using static/reserve ip. When i set that, the phone will keep on registering. In the switches side, i configure both data vlan and voice vlan to dhcp.

I heard from others that i will need to configure my ip phone to static in order to make it works.

Please advise if this is true ? if not any other steps i need to configure to make it work ?

Thank you so much in advance.

[Jonathan Schulenberg · Accepted solution]

This question can’t be answered without knowledge of how the switch is configured. Generally speaking, the IP address - dynamic or static - of one client have nothing to do with the operation of another except in cases of conflict (ie two hosts trying to use the same address concurrently). Separate VLANs makes this Address conflict part impossible. There are features where this could become a problem though. Most likely of those would be the Catalyst Integrated Security Toolkit (aka Layer 2 Security of First Hop Security), namely Dynamic ARP Inspection which leverages DHCP Snooping.

https://www.cisco.com/c/dam/en_us/solutions/industries/docs/gov/turniton_cisf.pdf

Another might be some AAA/NAC solution that expects a DHCP DORA to compete for certain policy triggers to apply.

[zheepern0826]

Hi Jonathan,

We have configured dhcp for data vlan and voice vlan. There is some ip form the data vlan we exclude out.

Wall jack -- IP Phone -- Workstation

When i connect the ip phone to the wall jack, it is working fine. When i connect the cable from my workstation to the ip phone, it is working fine and is able to grab the DHCP IP.

When i tried to configure static IP to the workstation, I notice my IP Phone is going to registering and continuous registering.

I am just curious why it is not working which theoretically it should works.